
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            width: 800px;
            height: 300px;
            background-color: rgb(96, 98, 98);

            display: flex;
            flex-direction: row;
            flex-wrap: nowrap;
            justify-content: space-between;
        }
        div span:nth-child(1){
            border: 1px solid #ffffff;
            width: 100px;
            height: 100px;
            background-color: rgb(109, 140, 140);
            /* 修改某个盒子在侧轴上的位置 */
            align-self: flex-end;
        }
        div span:nth-child(2){
            flex: 1;
            background-color: rgb(50, 146, 146);
            height: 100px;
            border: 1px solid #ffffff;

        }
        div span:nth-child(3){
            border: 1px solid #ffffff;
            width: 100px;
            height: 100px;
            background-color: rgb(109, 140, 140);
        }

    </style>
</head>
<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
    </div>

</body>
</html>